Introduction: Arduino+GSM+PIR= Awesome

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In present time Home/Office and many other place security is most important. In our absence these places are not secure. For make these palaces secure many peoples keep guards and many people prefer electronic security systems. In present time many types of security systems are available in market. These security systems are very accurate and easy to control and cheaply available and the most important thing is that they can be operated on low Voltage (Up to 12 Voltage).

Here we have tried making a simple arduino based security system using a GSM module and a PIR sensor. It gives a call to a pre specified phone number when any kind of intrusion is found. In the below pictures you could see the implementation of this security system.

Step 1: Grab the Components

The special thing abt this project is that the components are easily available if you quite do these stuffs related to electroincs.

1. 1x Arduino Uno

2. 1x SIM 300 GMS module

3. 1x PIR sensor

4. 2x Power supply (I used 12 v adaptor as they are preety handy) or 9v battery

5. Working SIM Card

6. Connecting wires

Components used are pretty basic .It is not compulsary that we use same GSM module there are loads of module in GSM ,you can use.

Step 2: Component Description for Deep Understanding


Arduino is an open-source microcontroller development board. In plain English, you can use the Arduino to read sensors and control things like motors and lights. This allows you to upload programs to this board which can then interact with things in the real world. With this, you can make devices which respond and react to the world at large.For instance, you can read a humidity sensor connected to a potted plant and turn on an automatic watering system if it gets too dry. Or, you can make a stand-alone chat server which is plugged into your internet router. Or, you can have it tweet every time your cat passes through a pet door. Or, you can have it start a pot of coffee when your alarm goes off in the morning.Basically, if there is something that is in any way controlled by electricity, the Arduino can interface with it in some manner. And even if it is not controlled by electricity, you can probably still use things which are (like motors and electromagnets), to interface with it.The possibilities of the Arduino are almost limitless. As such, there is no way that one single tutorial can cover everything you might ever need to know. That said, I've done my best to give a basic overview of the fundamental skills and knowledge that you need to get your Arduino up and running. If nothing more, this should function as a springboard into further experimentation and learning.


PIR sensors are used to detect living being movement. PIR is a Passive Infrared sensor, which detect infrared rays. All living being with a temperature above absolute zero emits heat energy in the form of radiation. These radiation are infrared ray. Human eye cannot see these rays because these rays are radiated at infrared wavelength. When any living being comes in range of PIR sensor, it detects heat of that living being and generate an output. PIR sensor module does not send any rays for detection, its only detects heat (Infrared). You can know more about PIR sensor in PIR sensor circuit.


This is a plug and play GSM Modem with a simple to interface serial interface. Use it to send SMS, make and receive calls, and do other GSM operations by controlling it through simple AT commands from micro controllers and computers. It uses the highly popular SIM300 module for all its operations. It comes with a standard RS232 interface which can be used to easily interface the modem to micro controllers and computers.

The modem consists of all the required external circuitry required to start experimenting with the SIM300 module like the power regulation, external antenna, SIM Holder, etc.


Uses the extremely popular SIM300 GSM moduleProvides the industry standard serial RS232 interface for easy connection to computers and other devicesProvides serial TTL interface for easy and direct interface to microcontrollersPower, RING and Network LEDs for easy debuggingOnboard 3V Lithium Battery holder with appropriate circuitry for providing backup for the modules’ internal RTCCan be used for GSM based Voice communications, Data/Fax, SMS,GPRS and TCP/IP stackCan be controlled through standard AT commandsComes with an onboard wire antenna for better reception.Board provides an option for adding an external antenna through an SMA connectorThe SIM300 allows an adjustable serial baud rate from 1200 to 115200 bps (9600 default)Modem a low power consumption of 0.25 A during normal operations and around 1 A during transmission Operating Voltage: 7 – 15V AC or DC (board has onboard rectifier

4. DC adaptor

They take AC Power (Usually 120V or 240V, or anywhere in between), and transform it to DC power, usually between 12V.

Step 3: Connection Time

System diagram of the security system is shown.

Connection are as follows..

RX of Arduino--> PIN 2 OF GSM module

TX of Arduino--> PIN 3 OF GSM module

Please make sure the jumpers are correctly placed as attached picture
This will allow the chip to know if it is dealing with a PC. Place a valid SIM card preferably no pin code. · Connect Power adapter to GSM

Provide respective Power supply using DC adaptor/9v Battery/etc

Output of PIR --> PIN 7 of Arduino

vcc of PIR-->5v of Arduino

Ground of PIR-->Gnd of Arduino

Step 4: Uploading Program to Arduino:

Just download the program or copy the code into an Arduino sketch
Codes are attached here by.


Download adjusted Software Serial library and place it in: C:\Users\user\Documents\Arduino\libraries.Unless it wont work for you.

Step 5: Finalizing.

After doing connection as per the circuit diagram and uploading codes to arduino .Now insert a valid/working sim card .
NOTE: Don't forget to place your sim card phone number in the code .this number is of your receiving number on which you will get a call alert when you are not at home/office.

And thats it.!!
You have made your own call alert system. Now whenany human (thief) comes in the range of PIR sensor, Arduino make a call to a fixed number. It means anybody in your house/office, then you can take a possible action against thief at same time and protect your own expensive things and life.
This marks the end of this instructable. Hope you liked it. Please vote for the project and share if you think it was awesome. Don't forget to follow for more cool projects!!
Fell free to have any query.
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